研究者詳細 - 田岡　俊昭

論文 - 田岡　俊昭

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Neu rofluid as Assessed by Diffusion-Weighted Imaging 国際誌 Open Access

Taoka, T

MAGNETIC RESONANCE IMAGING CLINICS OF NORTH AMERICA 29 巻 ( 2 ) 頁： 243 - 251 2021年5月

Associations among Cognitive Functions, Plasma DNA, and Diffusion Tensor Image along the Perivascular Space (DTI-ALPS) in Patients with Parkinson's Disease 国際共著国際誌 Open Access

Chen, HL; Chen, PC; Lu, CH; Tsai, NW; Yu, CC; Chou, KH; Lai, YR; Taoka, T; Lin, WC

OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021 巻頁： 4034509 - 4034509 2021年2月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Oxidative Medicine and Cellular Longevity

Background. Parkinson's disease (PD) is a common neurodegenerative disease associated with accumulation of misfolding proteins and increased neuroinflammation, which may further impair the glymphatic system. The purpose of this study was to utilize diffusion tensor image analysis along the perivascular space (DTI-ALPS) to evaluate glymphatic system activity and its relationship with systemic oxidative stress status in PD patients. Methods. Magnetic resonance imaging and neuropsychological tests were conducted on 25 PD patients with normal cognition (PDN), 25 PD patients with mild cognitive impairment (PD-MCI), 38 PD patients with dementia (PDD), and 47 normal controls (NC). Oxidative stress status was assessed by plasma DNA level. Differences in ALPS-index among the subgroups were assessed and further correlated with cognitive functions and plasma DNA levels. Results. The PD-MCI and PDD groups showed significantly lower ALPS-index compared to normal controls. The ALPS-index was inversely correlated with plasma nuclear DNA, mitochondrial DNA levels, and cognitive scores. Conclusions. Lower diffusivity along the perivascular space, represented by lower ALPS-index, indicates impairment of the glymphatic system in PD patients. The correlation between elevated plasma nuclear DNA levels and lower ALPS-index supports the notion that PD patients may exhibit increased oxidative stress associated with glymphatic system microstructural alterations.

DOI： 10.1155/2021/4034509

ISMRM2020における富樫かおり先生のGold Medal受賞と長縄慎二先生のSenior Fellow選出を記念して Open Access

黒田輝, 小畠隆行, 三木幸雄, 田岡俊昭

日本磁気共鳴医学会雑誌 41 巻 ( 1 ) 頁： 1 - 4 2021年2月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：日本磁気共鳴医学会

<p>　2020年8月にウェブ開催されたISMRM（国際磁気共鳴医学会）において，京都大学の富樫かおり先生がGold Medalを受賞され，名古屋大学の長縄慎二先生がSenior Fellowに選出されました．同じ年の大会で日本人が同時に2名選出されることは初めてのことであり，MRI研究における日本の大きなプレゼンスを示す出来事でもありました．</p><p>　この度，この快挙を記念して，お二人とご縁の深い先生方からの特別寄稿をいただきましたので，ここに掲載させて頂きます．</p>

DOI： 10.2463/jjmrm.2020-1724

Evaluating the Effect of Arterial Pulsation on Cerebrospinal Fluid Motion in the Sylvian Fissure of Patients with Middle Cerebral Artery Occlusion Using Low b-value Diffusion-weighted Imaging Open Access

Taoka, T; Kawai, H; Nakane, T; Abe, T; Nakamichi, R; Ito, R; Sasaki, Y; Nishida, A; Naganawa, S

MAGNETIC RESONANCE IN MEDICAL SCIENCES 20 巻 ( 4 ) 頁： 371 - 377 2021年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Magnetic Resonance in Medical Sciences

Purpose: Decrease in signal of the cerebrospinal fluid (CSF) on low b-value diffusion weighted image (DWI) due to non-uniform flow can provide additional information regarding CSF motion. The purpose of the current study was to evaluate whether arterial pulsations constitute the driving force of CSF motion. Methods: We evaluated the CSF signals within the Sylvian fissure on low b-value DWI in 19 patients with unilateral middle cerebral artery (MCA) occlusion. DWI with b-value of 500 s/mm2 was evaluated for a decrease in CSF signal within the Sylvian fissure including the Sylvian vallecula and lower, middle, and higher Sylvian fissures and graded as follows: the same as contralateral side; smaller signal decrease than that on contralateral side; and no signal decrease. MR angiography (MRA) findings of MCA were graded as follows: the same as contralateral, lower signal than contralateral signal, and no signal. In 15 patients, regional cerebral blood flow (rCBF) was evaluated using single-photon emission computed tomography (SPECT) studies and graded as > 90%, 90%–70%, and < 70% rCBF compared to contralateral. The correlations between the gradings were evaluated using G likelihood-ratio test. Results: There was no statistically significant correlation between the MRA and low b-value DWI gradings of CSF in all areas. There were statistically significant correlations between the decreases in CBF on SPECT and CSF signals in the middle Sylvian fissure. Conclusion: The driving force of CSF pulsation in the Sylvian sinus may be related to the pulsations of the cerebral hemisphere rather than direct arterial pulsations.

DOI： 10.2463/mrms.mp.2020-0121

Relationship between Parasagittal Perivenous Cysts and Leakage of Gadolinium-based Contrast Agents into the Subarachnoid Space around the Cortical Veins after Intravenous Administration 査読有り Open Access

Naganawa, S; Ito, R; Nakamichi, R; Kawamura, M; Kawai, H; Taoka, T; Yoshida, T; Sone, M

MAGNETIC RESONANCE IN MEDICAL SCIENCES 20 巻 ( 3 ) 頁： 245 - 252 2021年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Magnetic Resonance in Medical Sciences

Purpose: The purpose of this retrospective study was to investigate the relationship between the number and size of cystic structures around the cortical veins near the superior sagittal sinus and the leakage of gadolinium-based contrast agent (GBCA) around the cortical veins. Methods: Of 190 patients (91 male and 99 female), that were scanned at 4 h after an intravenous injection of GBCA as a diagnostic examination for endolymphatic hydrops, 6 patients with GBCA leakage were younger than the previously proposed threshold age of 37.3 years for leakage. Six age-matched patients without leakage were also included for reference. In addition, we included 8 cases without leakage that were older than the hypothesized threshold of 37.3 years, as well as 8 age-matched patients with GBCA leakage into the cerebrospinal fluid space. The number of cysts was counted and the sizes were measured in these 28 patients (age: 32–60 years old, 13 men and 15 women). Results: The mean number of cysts surrounding the cortical veins in the parasagittal region was 4.29 ± 1.77 vs. 1.79 ± 1.05 (P = 0.0001) in the subjects with and without GBCA leakage, respectively. The mean size of the largest cysts was at 8.89 ± 3.49 mm vs. 5.69 ± 2.29 (P = 0.009) in the subjects with and without GBCA leakage, respectively. Conclusion: The number and size of the perivenous cystic structures near the superior sagittal sinus is greater in subjects with GBCA leakage into the subarachnoid space compared with those without leakage. Future research regarding the histological and functional details of these parasagittal cystic structures is needed.

DOI： 10.2463/mrms.mp.2020-0062

Intracranial Distribution of Intravenously Administered Gadolinium-based Contrast Agent over a Period of 24 Hours: Evaluation with 3D-real IR Imaging and MR Fingerprinting 査読有り Open Access

Naganawa, S; Ito, R; Kato, Y; Kawai, H; Taoka, T; Yoshida, T; Maruyama, K; Murata, K; Körzdörfer, G; Pfeuffer, J; Nittka, M; Sone, M

MAGNETIC RESONANCE IN MEDICAL SCIENCES 20 巻 ( 1 ) 頁： 91 - 98 2021年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Magnetic Resonance in Medical Sciences

Purpose: To evaluate the feasibility for the detection of slight contrast effects after intravenous administration of single dose gadolinium-based contrast agent (IV-SD-GBCA), the time course of the GBCA distribution up to 24 h was examined in various fluid spaces and brain parenchyma using 3D-real IR imaging and MR fingerprinting (MRF). Methods: Twenty-four patients with a suspicion of endolymphatic hydrops were scanned at pre-administration and at 10 min, 4 and 24 h post-IV-SD-GBCA. 3D-real IR images and MRF at the level of the internal auditory canal were obtained. The signal intensity on the 3D-real IR image of the cerebrospinal fluid (CSF) in the cerebellopontine angle cistern (CPA), Sylvian fissure (Syl), lateral ventricle (LV), and cochlear perilymph (CPL) was measured. The T1 and T2 values of cerebellar gray (GM) and white matter (WM) were measured using MRF. Each averaged value at the various time points was compared using an analysis of variance. Results: The signal intensity on the 3D-real IR image in each CSF region peaked at 4 h, and was decreased significantly by 24 h (P < 0.05). All patients had a maximum signal intensity at 4 h in the CPA, and Syl. The mean CPL signal intensity peaked at 4 h and decreased significantly by 24 h (P < 0.05). All patients but two had a maximum signal intensity at 4 h. Regarding the T1 value in the cerebellar WM and GM, the T1 value at 10 min post-IV-GBCA was significantly decreased compared to the pre-contrast scan, but no significant difference was observed at the other time points. There was no significant change in T2 in the gray or white matter at any of the time points. Conclusion: Time course of GBCA after IV-SD-GBCA could be evaluated by 3D-real IR imaging in CSF spaces and in the brain by MRF.

DOI： 10.2463/mrms.mp.2020-0030

Relationship between Time-dependent Signal Changes in Parasagittal Perivenous Cysts and Leakage of Gadolinium-based Contrast Agents into the Subarachnoid Space Open Access

Naganawa, S; Ito, R; Nakamichi, R; Kawamura, M; Taoka, T; Yoshida, T; Sone, M

MAGNETIC RESONANCE IN MEDICAL SCIENCES 20 巻 ( 4 ) 頁： 378 - 384 2021年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Magnetic Resonance in Medical Sciences

Purpose: To investigate the association between signal changes over time in perivenous cystic structures near the superior sagittal sinus and leakage of a gadolinium-based contrast agent (GBCA) into the subarachnoid space in patients with suspected endolymphatic hydrops. Methods: Fifty-one cystic structures in 27 cases were evaluated. The signal intensity of the cystic structures was measured on 3D real inversion recovery (3D-real IR) images obtained at pre-, and at 10 min, 4 hrs and 24 hrs post-intravenous administration (IV) of GBCA. Signal enhancement of the cystic structures from the pre-contrast images at each time point was compared in subjects with leakage (positive) versus those without leakage (negative) using an ANOVA. Fisher’s exact probability test was used to compare the maximum contrast-enhanced time point between positive and negative groups. We used 5% as a threshold to determine statistical significance. Results: In leakage positive subjects, mean signal enhancement of the cysts was significantly greater at 4 and 24 hrs compared to 10 min. However, although there was a trend of an increase from 4 to 24 hrs, the difference was not significant. In the leakage negative group, mean signal enhancement of the cysts was significantly higher at 4 hrs compared to 10 min and 24 hrs. There was no significant difference between 10 min and 24 hrs. In the positive group, the maximum signal increase was found in 10/38 and 28/38 cysts at 4 and 24 hrs after IV-GBCA, respectively. In the leakage negative group, the maximum signal increase was found in 10/13 and 3/13 cysts at 4 and 24 hrs, respectively (P = 0.0019). Conclusion: There was an association between signal changes over time after IV-GBCA in perivenous cystic structures and leakage of GBCA. Further research to clarify the impact of cystic structures on the function of the waste clearance system of the brain is warranted.

DOI： 10.2463/mrms.mp.2020-0138

Neurofluid Dynamics and the Glymphatic System: A Neuroimaging Perspective 国際誌 Open Access

Taoka, T; Naganawa, S

KOREAN JOURNAL OF RADIOLOGY 21 巻 ( 11 ) 頁： 1199 - 1209 2020年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Korean Journal of Radiology

The glymphatic system hypothesis is a concept describing the clearance of waste products from the brain. The term “glymphatic system” combines the glial and lymphatic systems and is typically described as follows. The perivascular space functions as a conduit that drains cerebrospinal fluid (CSF) into the brain parenchyma. CSF guided to the perivascular space around the arteries enters the interstitium of brain tissue via aquaporin-4 water channels to clear waste proteins into the perivascular space around the veins before being drained from the brain. In this review, we introduce the glymphatic system hypothesis and its association with fluid dynamics, sleep, and disease. We also discuss imaging methods to evaluate the glymphatic system.

DOI： 10.3348/kjr.2020.0042

Increased Dendritic Orientation Dispersion in the Left Occipital Gyrus is Associated with Atypical Visual Processing in Adults with Autism Spectrum Disorder 査読有り国際誌

Matsuoka, K; Makinodan, M; Kitamura, S; Takahashi, M; Yoshikawa, H; Yasuno, F; Ishida, R; Kishimoto, N; Yasuda, Y; Hashimoto, R; Taoka, T; Miyasaka, T; Kichikawa, K; Kishimoto, T

CEREBRAL CORTEX 30 巻 ( 11 ) 頁： 5617 - 5625 2020年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Cerebral Cortex

In autism spectrum disorder (ASD), the complexity-specific hypothesis explains that atypical visual processing is attributable to selective functional changes in visual pathways. We investigated dendritic microstructures and their associations with functional connectivity (FC). Participants included 28 individuals with ASD and 29 typically developed persons. We explored changes in neurite orientation dispersion and density imaging (NODDI) and brain areas whose FC was significantly correlated with NODDI parameters in the explored regions of interests. Individuals with ASD showed significantly higher orientation dispersion index (ODI) values in the left occipital gyrus (OG) corresponding to the secondary visual cortex (V2). FC values between the left OG and the left middle temporal gyrus (MTG) were significantly negatively correlated with mean ODI values. The mean ODI values in the left OG were significantly positively associated with low registration of the visual quadrants of the Adolescent/Adult Sensory Profile (AASP), resulting in a significant positive correlation with passive behavioral responses of the AASP visual quadrants; additionally, the FC values between the left OG and the left MTG were significantly negatively associated with reciprocal social interaction. Our results suggest that abnormal V2 dendritic arborization is associated with atypical visual processing by altered intermediation in the ventral visual pathway.

DOI： 10.1093/cercor/bhaa121

Aging Impacts the Overall Connectivity Strength of Regions Critical for Information Transfer Among Brain Networks Open Access

Bagarinao, E; Watanabe, H; Maesawa, S; Mori, D; Hara, K; Kawabata, K; Yoneyama, N; Ohdake, R; Imai, K; Masuda, M; Yokoi, T; Ogura, A; Taoka, T; Koyama, S; Tanabe, HC; Katsuno, M; Wakabayashi, T; Kuzuya, M; Hoshiyama, M; Isoda, H; Naganawa, S; Ozaki, N; Sobue, G

FRONTIERS IN AGING NEUROSCIENCE 12 巻頁： 592469 2020年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Frontiers in Aging Neuroscience

Recent studies have demonstrated that connector hubs, regions considered critical for the flow of information across neural systems, are mostly involved in neurodegenerative dementia. Considering that aging can significantly affect the brain’s intrinsic connectivity, identifying aging’s impact on these regions’ overall connection strength is important to differentiate changes associated with healthy aging from neurodegenerative disorders. Using resting state functional magnetic resonance imaging data from a carefully selected cohort of 175 healthy volunteers aging from 21 to 86 years old, we computed an intrinsic connectivity contrast (ICC) metric, which quantifies a region’s overall connectivity strength, for whole brain, short-range, and long-range connections and examined age-related changes of this metric over the adult lifespan. We have identified a limited number of hub regions with ICC values that showed significant negative relationship with age. These include the medial precentral/midcingulate gyri and insula with both their short-range and long-range (and thus whole-brain) ICC values negatively associated with age, and the angular, middle frontal, and posterior cingulate gyri with their long-range ICC values mainly involved. Seed-based connectivity analyses further confirmed that these regions are connector hubs with connectivity profile that strongly overlapped with multiple large-scale brain networks. General cognitive performance was not associated with these hubs’ ICC values. These findings suggest that even healthy aging could negatively impact the efficiency of regions critical for facilitating information transfer among different functional brain networks. The extent of the regions involved, however, was limited.

DOI： 10.3389/fnagi.2020.592469

Change of White Matter Integrity in Children With Hematopoietic Stem Cell Transplantation 国際誌

Sakaguchi, Y; Natsume, J; Kidokoro, H; Tanaka, M; Okai, Y; Ito, Y; Yamamoto, H; Ohno, A; Nakata, T; Nakane, T; Kawai, H; Taoka, T; Muramatsu, H; Naganawa, S; Takahashi, Y

PEDIATRIC NEUROLOGY 111 巻頁： 78 - 84 2020年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Pediatric Neurology

Background: Advances in hematopoietic stem cell transplantation have improved the survival rate of malignant diseases and congenital immunodeficiencies. It has become important to assess long-term complications in survivors. To assess neurological abnormalities in children treated by transplantation, diffusion tensor imaging was performed. Methods: Forty children who underwent head diffusion tensor imaging before and after their first transplantation were enrolled. Patients with brain lesions on conventional MRI were excluded. Fractional anisotropy and mean diffusivity were compared between patients and 28 control subjects using tract-based spatial statistics. The Strengths and Difficulties Questionnaire was administered as a behavioral evaluation after transplantation, and diffusion tensor images of patients with and without behavioral abnormalities were compared. Results: The age of patients and controls was 0 to 19 years and 0 to 16 years, respectively. The date of diffusion tensor imaging was 10 to 57 days before and 40 to 153 days after transplantation. Tract-based spatial statistics showed fractional anisotropy reduction in widespread white matter in patients before and after transplantation. Mean diffusivity was high before transplantation and normalized after transplantation. Analysis comparing before and after hematopoietic stem cell transplantation shows no difference in fractional anisotropy and significantly high mean diffusivity before hematopoietic stem cell transplantation. In patients with behavioral abnormalities, low fractional anisotropy and high mean diffusivity remained after transplantation. Conclusions: Longitudinal diffusion tensor imaging showed white matter abnormalities in children without conventional MRI abnormalities, which were related to behavioral problems after transplantation. Diffusion tensor imaging is useful for behavioral assessment in children undergoing transplantation.

DOI： 10.1016/j.pediatrneurol.2020.06.008

特集時系列から学ぶ中枢神経疾患の画像診断-MR Retroscopy- Ⅳ.脊髄　1 頸髄の変形と異常信号

田岡俊昭

画像診断 40 巻 ( 10 ) 頁： 1100 - 1103 2020年8月

Changes in white matter fiber density and morphology across the adult lifespan: A cross-sectional fixel-based analysis 国際誌 Open Access

Choy, SW; Bagarinao, E; Watanabe, H; Ho, ETW; Maesawa, S; Mori, D; Hara, K; Kawabata, K; Yoneyama, N; Ohdake, R; Imai, K; Masuda, M; Yokoi, T; Ogura, A; Taoka, T; Koyama, S; Tanabe, HC; Katsuno, M; Wakabayashi, T; Kuzuya, M; Hoshiyama, M; Isoda, H; Naganawa, S; Ozaki, N; Sobue, G

HUMAN BRAIN MAPPING 41 巻 ( 12 ) 頁： 3198 - 3211 2020年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Human Brain Mapping

White matter (WM) fiber bundles change dynamically with age. These changes could be driven by alterations in axonal diameter, axonal density, and myelin content. In this study, we applied a novel fixel-based analysis (FBA) framework to examine these changes throughout the adult lifespan. Using diffusion-weighted images from a cohort of 293 healthy volunteers (89 males/204 females) from ages 21 to 86 years old, we performed FBA to analyze age-related changes in microscopic fiber density (FD) and macroscopic fiber morphology (fiber cross section [FC]). Our results showed significant and widespread age-related alterations in FD and FC across the whole brain. Interestingly, some fiber bundles such as the anterior thalamic radiation, corpus callosum, and superior longitudinal fasciculus only showed significant negative relationship with age in FD values, but not in FC. On the other hand, some segments of the cerebello-thalamo-cortical pathway only showed significant negative relationship with age in FC, but not in FD. Analysis at the tract-level also showed that major fiber tract groups predominantly distributed in the frontal lobe (cingulum, forceps minor) exhibited greater vulnerability to the aging process than the others. Differences in FC and the combined measure of FD and cross section values observed between sexes were mostly driven by differences in brain sizes although male participants tended to exhibit steeper negative linear relationship with age in FD as compared to female participants. Overall, these findings provide further insights into the structural changes the brain's WM undergoes due to the aging process.

DOI： 10.1002/hbm.25008

Steroid-responsive recurrent tumefactive demyelination with multiple petechial hemorrhages along non-displaced medullary veins 査読有り国際誌

Tsuboi, T; Harada, Y; Suzuki, M; Ando, T; Atsuta, N; Ohka, F; Takeuchi, K; Taoka, T; Ohba, S; Nakaguro, M; Abe, M; Nakashima, I; Yoshida, M; Katsuno, M

CLINICAL NEUROLOGY AND NEUROSURGERY 193 巻頁： 105764 - 105764 2020年6月

White matter microstructural changes in tuberous sclerosis: Evaluation by neurite orientation dispersion and density imaging (NODDI) and diffusion tensor images 査読有り国際誌 Open Access

Taoka, T; Aida, N; Fujii, Y; Ichikawa, K; Kawai, H; Nakane, T; Ito, R; Naganawa, S

SCIENTIFIC REPORTS 10 巻 ( 1 ) 頁： 436 - 436 2020年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Scientific Reports

Neurite orientation dispersion and density imaging (NODDI) is a novel diffusion method for evaluating tissue microstructure, and may provide additional information over conventional diffusion tensor imaging (DTI). We evaluated NODDI and DTI parameters in cases of tuberous sclerosis (TS) to assess microstructural changes in the white matter. Eleven cases of tuberous sclerosis and eight age-matched controls underwent NODDI and DTI. We performed qualitative analysis and tract-based spatial statistics (TBSS) analysis of the NODDI parameters (Ficv: intracellular volume fraction, Fiso: isotropic fraction, ODI: orientation dispersion index) as well as DTI parameters (MD: mean diffusivity, FA: fractional anisotropy). We also performed a correlation analysis between clinical symptoms and parameters. The qualitative analysis indicated that the Ficv had a lower value in TS cases particularly in the tubers adjacent to the white matter. The TBSS analysis showed that the TS cases had decreased Ficv in a greater area compared to the other parameters including MD. In particular, the Ficv was decreased in deep white matter, such as the superior longitudinal fascicles (SLF). The application of NODDI to TS cases revealed tissue microstructural changes, and particularly the Ficv could detect more widespread abnormalities in white matter structure compared to DTI parameters.

DOI： 10.1038/s41598-019-57306-w

Glymphatic imaging using MRI 査読有り国際誌 Open Access

Taoka, T; Naganawa, S

JOURNAL OF MAGNETIC RESONANCE IMAGING 51 巻 ( 1 ) 頁： 11 - 24 2020年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Magnetic Resonance Imaging

In recent years, the existence of a mass transport system in the brain via cerebrospinal fluid (CSF) or interstitial fluid (ISF) has been suggested by many studies. The glymphatic system is hypothesized to be a waste clearance system of the CSF through the perivascular and interstitial spaces in the brain. Tracer studies have primarily been used to visualize or evaluate the waste clearance system in the brain, and evidence for this system has accumulated. The initial study that identified the glymphatic system was an in vivo tracer study in mice. In that study, fluorescent tracers were injected into the cisterna magna and visualized by two-photon microscopy. MRI has also been used to evaluate glymphatic function primarily with gadolinium-based contrast agents (GBCAs) as tracers. A number of GBCA studies evaluating glymphatic function have been conducted using either intrathecal or intravenous injections. Stable isotopes, such as 17O-labeled water, may also be used as tracers since they can be detected by MRI. In addition to tracer studies, several other approaches have been used to evaluate ISF dynamics within the brain, including diffusion imaging. Phase contrast evaluation is a powerful method for visualizing flow within the CSF space. In order to evaluate the movement of water within tissue, diffusion-weighted MRI represents another promising technique, and several studies have utilized diffusion techniques for the evaluation of the glymphatic system. This review will discuss the findings of these diffusion studies. Level of Evidence: 5. Technical Efficacy: Stage 3. J. Magn. Reson. Imaging 2019. J. Magn. Reson. Imaging 2020;51:11–24.

DOI： 10.1002/jmri.26892

Comprehensive Evaluation of <i>B</i><sub>1</sub><SUP>+</SUP>-corrected FISP-based Magnetic Resonance Fingerprinting: Accuracy, Repeatability and Reproducibility of T<sub>1</sub> and T<sub>2</sub> Relaxation Times for ISMRM/NIST System Phantom and Volunteers 査読有り Open Access

Kato, Y; Ichikawa, K; Okudaira, K; Taoka, T; Kawaguchi, H; Murata, K; Maruyama, K; Koerzdoerfer, G; Pfeuffer, J; Nittka, M; Naganawa, S

MAGNETIC RESONANCE IN MEDICAL SCIENCES 19 巻 ( 3 ) 頁： 168 - 175 2020年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Magnetic Resonance in Medical Sciences

Purpose: This study aimed to evaluate comprehensively; accuracy, repeatability and reproducibility of T1 and T2 relaxation times measured by magnetic resonance fingerprinting using B+1-corrected fast imaging with steady-state precession (FISP–MRF). Methods: The International Society of Magnetic Resonance in Medicine/National Institute of Standards and Technology (ISMRM/NIST) phantom was scanned for 100 days, and six healthy volunteers for 5 days using a FISP–MRF prototype sequence. Accuracy was evaluated on the phantom by comparing relaxation times measured by FISP–MRF with the reference values provided by the phantom manufacturer. Daily repeatability was characterized as the coefficient of variation (CV) of the measurements over 100 days for the phantom and over 5 days for volunteers. In addition, the cross-scanner reproducibility was evaluated in volunteers. Results: In the phantom study, T1 and T2 values from FISP–MRF showed a strong linear correlation with the reference values of the phantom (R2 = 0.9963 for T1; R2 = 0.9966 for T2). CVs were <1.0% for T1 values larger than 300 ms, and <3.0% for T2 values across a wide range. In the volunteer study, CVs for both T1 and T2 values were <5.0%, except for one subject. In addition, all T2 values estimated by FISP–MRF in vivo were lower than those measured with conventional mapping sequences reported in previous studies. The cross-scanner variation of T1 and T2 showed good agreement between two different scanners in the volunteers. Conclusion: B+1-corrected FISP-MRF showed an acceptable accuracy, repeatability and reproducibility in the phantom and volunteer studies.

DOI： 10.2463/mrms.mp.2019-0016

The Space between the Pial Sheath and the Cortical Venous Wall May Connect to the Meningeal Lymphatics 査読有り Open Access

Naganawa, S; Ito, R; Taoka, T; Yoshida, T; Sone, M

MAGNETIC RESONANCE IN MEDICAL SCIENCES 19 巻 ( 1 ) 頁： 1 - 4 2020年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Magnetic Resonance in Medical Sciences

We currently obtain pre-and post-contrast enhanced whole brain 3D-real inversion recovery images for the evaluation of endolymphatic hydrops. We noticed that the space between the pial sheath surrounding the cortical veins and the cortical venous wall is enhanced and this enhancement seems to connect to the meningeal lymphatics along superior sagittal sinus. This new anatomical concept regarding the outflow from the glymphatic system might be important for the future research in neuroscience.

DOI： 10.2463/mrms.bc.2019-0099

Detection of IV-gadolinium Leakage from the Cortical Veins into the CSF Using MR Fingerprinting 査読有り Open Access

Naganawa, S; Nakane, T; Kawai, H; Taoka, T; Kawaguchi, H; Maruyama, K; Murata, K; Körzdörfer, G; Pfeuffer, J; Nittka, M; Sone, M

MAGNETIC RESONANCE IN MEDICAL SCIENCES 19 巻 ( 2 ) 頁： 141 - 146 2020年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Magnetic Resonance in Medical Sciences

Purpose: It has been reported that leakage of intravenously administered gadolinium-based contrast agents (IV-GBCAs) into the cerebrospinal fluid (CSF) from the cortical veins even in healthy subjects can be detected using a highly sensitive pulse sequence such as heavily T2-weighted 3D fluid-attenuated inversion recovery and 3D-real inversion recovery (IR). The purpose of this study was to evaluate the feasibility of MR fingerprinting to detect GBCA leakage from the cortical veins after IV-GBCA. Materials: Fourteen patients with suspected endolymphatic hydrops (EH) who received a single dose of IV-GBCA (39–79 years old) were included. The real IR images as well as MR fingerprinting images were obtained at 4 h after IV-GBCA. T1 and T2 values were obtained using MR fingerprinting and analyzed in ROIs covering intense GBCA leakage, and non-leakage areas of the CSF as determined on real IR images. The scan time for real IR imaging was 10 min and that for MR fingerprinting was 41 s. Results: The mean T1 value of the ROI in the area of GBCA leakage was 2422 ± 261 ms and that in the non-leakage area was 3851 ± 235 ms (P < 0.01). There was no overlap between the T1 values in the area of GBCA leakage and those in the non-leakage area. The mean T2 value in the area of GBCA leakage was 319 ± 90 ms and that in the non-leakage area was 670 ± 166 ms (P < 0.01). There was some overlap between the T2 values in the area of GBCA leakage and those in the non-leakage area. Conclusion: Leaked GBCA from the cortical veins into the surrounding CSF can be detected using MR fingerprinting obtained in <1 min.

DOI： 10.2463/mrms.mp.2019-0048

Confirmation of Age-dependence in the Leakage of Contrast Medium around the Cortical Veins into Cerebrospinal Fluid after Intravenous Administration of Gadolinium-based Contrast Agent 査読有り Open Access

Naganawa, S; Ito, R; Kawai, H; Taoka, T; Yoshida, T; Sone, M

MAGNETIC RESONANCE IN MEDICAL SCIENCES 19 巻 ( 4 ) 頁： 375 - 381 2020年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Magnetic Resonance in Medical Sciences

Purpose: It has been reported previously that intravenously administered gadolinium-based contrast agent (GBCA) leaks into the subarachnoid space around the cortical veins at 4 h after injection in all old people over 37 years, but not in younger people up to 37 years of age in 3D-real IR images. The purpose of this study was to investigate whether there was a strict threshold of 37 years of age for the leakage of the GBCA into the subarachnoid space. Methods: The subjects included 190 patients, that were scanned for 3D-real IR images at 4 hours after intravenous injection of GBCA as a diagnostic test for endolymphatic hydrops. The patient’s age ranged from 14 to 81 years. Two experienced neuroradiologists evaluated the images to determine whether the GBCA leakage around the cortical veins was positive or negative. Any discrepancies between the two observers were discussed and a consensus was obtained. A Mann–Whitney U test and receiver operating characteristic (ROC) curve analysis were used to compare the positive and the negative group and to set the age cut-off value for the prediction of GBCA leakage. Results: The GBCA leakage around the cortical veins was negative in 35 patients and positive in 155 patients. The average age was 33 ± 11 years in the negative group, and 55 ± 12 years in the positive group (P < 0.01). In the ROC analysis for the age and leakage of the GBCA, an area under the curve was 0.905 and the cut-off age was 37.317 years (sensitivity of 0.942 and specificity of 0.771). Conclusion: Intravenously administered GBCA leaks into the subarachnoid space around the cortical veins in most patients over 37 years of age. However, it should be noted that it can be found occasionally in patients under 37 years of age.

DOI： 10.2463/mrms.mp.2019-0182

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